Ruari

Ruari

Active Member
Whats the difference between a Military LT77 gear box and that from a Civvy vehicle. All I have found is that 1st & 2nd and geared lower in the military.
I was told but can't find anything to back it up that due to the gearing a military 90 (2.5na) will do 40mph top. Now that don't seem right to me as I could do more than that in my old 2,5na series.
 
Ruari said:
Whats the difference between a Military LT77 gear box and that from a Civvy vehicle. All I have found is that 1st & 2nd and geared lower in the military.
I was told but can't find anything to back it up that due to the gearing a military 90 (2.5na) will do 40mph top. Now that don't seem right to me as I could do more than that in my old 2,5na series.
Click to expand...

yes thats right 1st and 2nd are slightly lower geared the rest is the same ,the difference in top end is done through transfer box of which all 2.5s should be 1.667 but 1.410 could have later ben fitted in some ,its possible diffs are 4.7s instead of 3.54s ,youd have to count turns of prop or wheel
 
They did more than 40, I looked after a fleet of 30 or so and spent 9 years driving them, very rarely was low box needed unless on exercise or up a mountain in Bosnia etc.
When towing trailers we were ment to stick to 45 max, can't remember top speed but over 60, can't remember now what transfer box they had but my 200tdi box and ratios are fairly similar
 
my t box in my ex-mil 90 is a 1.410, tops out about 75mph (ish) but is fecking horrible over about 65mph, mainly cos of the racket as it has no sound deadening at all. It is happiest at 55-65mph on roads and loves low box off road, its quite a nice engine off road actually, well for the piddly 'off road' i have done lol
 
For me, 1st gear is too low for most situations. I guess it would be handy if your towing. 95% of the time, I set off in 2nd. 2nd is still so low that I can pull off without using the accelerator, so I don't feel that I'm putting any strain on the clutch. On a hill, I would use 1st just to give the clutch an east ride.

The step between 4th and 5th always seems too short to me, so much so, it's hard to tell which gear your in.

As for low range, 1st and 2nd are crazy low! I would be very surprised if you could do 40 mph in low 5th. My guess would be 20-25 max.
 
BTW, I would also say that the 2.5NA seems very at home off road in low range. The power band is smooth, easy to use and predictable.

I've yet to venture off road with my 200 TDI but I would imagine that one of the differences will be that you can get yourself into a whole heap of trouble, really quick! NA, you have thinking time. Can't wait to do some comparisons.
 
I have a neighbour who does driving instruction for the raf he swears by the 2.5na a lot better in the mud doesn't spin so easy and as spook said you get thinking time
 
Been there done that with the 2.5na.
Cashed in the car and got a toy, but now missing the toy for everyday as my pockets aren't that deep top run a V*
So dropping in a 200tdi - just need to check out the gearbox.

Very helpful chaps, time to look at the plates to see the ratios.
 
All this makes sense to me, my 2.5 n/a 90 started life as an ambulance and had an 11J engine in it so it follows that the gearbox would have been military as well, that explains the big gap between second and third which was exaggerated with the bigger wheels:)
 
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